import re
import requests

content = requests.get('http://book.douban.com').text
pattern = re.compile('<li.*?cover.*?href="(.*?)".*?title="(.*?)">.*?<span class="author">(.*?)</span>.*?class="year">(.*?)</span>.*?class="publisher">(.*?)</span>',re.S)
results = re.findall(pattern,content)
print(results)
for item in results:
    url,title,author,date = item
    author=re.sub('\s','',author)
    print(author)